Apparatus for tensioning strip material



May15, 1956 D. F. COLLINS APPARATUS FOR TENSIONING STRIP MATERIAL 4Sheets-Sheet 1 Filed May 24, 1952 IN VEN TOR. DON F. COLLINS ATTORNEYSFig. 2

May 15, 1956 D. F. COLLINS Filed May 24, 1952 VALVE 86 iOPEN H LVALVE 88CLOSED VALVE fi l '1 58 I, 58

v Fig. 3 66 65 56 I 56 '1!!!IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIlIIIII/l IN VEN TOR. DON F.COLLINS WW7 7 AIiORNEYS y 1 1956 D. F. COLLINS 2,745,134

APPARATUS FOR TENSIONING STRIP MATERIAL Filed May 24, 1952 4Sheets-Sheet 5 Fig. 5 25 INVENTOR. DON F. COLLINS ATTORNEYS M y 1956 D.F. COLLINS 2,745,134

APPARATUS FOR TENSIONING STRIP MATERIAL Filed May 24, 1952 4Sheets-Sway!v 4 DON F. COLLINS ATTORN EYS United States Patent APPARATUSnon rENsioNiNG STRIP MATERIAL Don F. Collins, Pontiac, Mich, assignor toBoston Woven Hose and Rubber Company, Cambridge, Mass., a cor-.

This invention comprises novel and useful improvements in apparatus fortensioning strip material. The invention relates particularly toimprovements in the stretching of rubber belting and the likepreparatory to vulcanizing it as shown in Reissue Patent No. 19,660dated July 30, 1935. This patent discloses a plurality of cylindricalrolls disposed to support strip material progressively looped arcuatelyon and about the rolls which are rotatably connected to rotate atprogressively increasing surface speeds adapted to stretch the materialtherebetween. a braked let-off reel that retards movement of thematerial to the rolls. A primary object of my invention resides in theproduction of novel apparatus for placing and maintaining an improved,more uniform and variable retarding eifect on the material passing tosaid rolls and to novel apparatus for placing any desired percentage ofstretch in the said material from zero to the maximum stretch for whichthe mechanism employed is constructed.

An important feature of the invention concerns the placing of saiddesired percentage of stretch in the material by passing it in arcuatelylooped frictional contact with a plurality of cylindrical surfacesdisposed selectively to give fixed increments of stretch to the materialbetween adjacent surfaces, placing and maintaining a selectivelyvariable stretch in the material in advance of said surfaces andstretching the material to said percentage of its length by adding suchof said fixed increments of stretch selectively thereto as will totalsaid desired percentage of stretch.

These and other features of the invention will be more readilyunderstood and appreciated from the following detailed description of apreferred embodiment thereof selected for purposes of illustration andshown in the accompanying drawings in which:

Fig. l is a front elevation, partially broken away, of a machineembodying the invention,

Fig. 2 is an enlarged front elevation of a portion of the machine,

Fig. 3 is a fragmentary elevation on line 3-3 of Fig. 2,

Fig. 4 is a fragmentary plan on line 4-4 of Fig. 2, partially brokenaway,

Fig. 5 is an enlarged fragmentary plan view partially in section takenon line 55 of Fig. 1,

Fig. 6 is a fragmentary front elevation of gearing shown in Figs. 1 and5, and

Fig. 7 is a schematic view illustrating pneumatically operated portionsof the machine.

In the accompanying drawings I have illustrated the invention inconjunction with a vulcanizing machine of the continuous type shown inPatent No. 2,039,271. This machine employs an endless steel pressureband 10 passing about supporting rolls 11 and 12 and having a reentrantloop therebetween passing about and in contact with a substantialarcuate portion of a vulcanizing drum 14. The drum is driven in thedirection of the arrows and the strip material 15 to be vulcanized isfed into the bite between the drum and the band above the roll 12. The

The material is drawn over the rolls fromice present invention comprisesimproved apparatus for stretching this material a desired percentage ofits length during its passage to the bite whereupon it is vulcanized insuch elongated condition. As illustrated in Fig. 1, the material isdrawn from a supply reel 16 and is stretched by my novel apparatusduring its passage therefrom to the bite.

As illustrated in Fig. 1, the strip material 15 passes from the supplyreel 16 over an idler 18, over and in arcuate contact with a cylindricalroll 20, thence into a U-shaped loop 21 about a dancer roll 22,-thenceover an idler 24, then in looped arcuate engagement on and about aplurality of cylindrical rolls 25, 26, 27 and 28 and thence under anidler 30 to the drum 14. During this passage, the material is given apredetermined tension at the U-shaped loop and thereafter sufficientfixedincrements of stretch provided between the rolls 25 to 28 and thedrum 14 are added to total the percentage of stretch required.

As hereinafter specifically described, the strip material 15 is given apredetermined initial stretch at the U-loop about the dancer roll 22,the amount of this tension and stretch being variable between zero and amaximum limit. The strip thereafter passes about the rolls 25-28 and tothe drum 14 where such additional increments of stretch are provided asto total the percentage of stretch desired. The rolls 2528 are fixed toshafts 32 rotatable in a frame 33. Gears 34 loose on these shafts areinterconnected by intermediate gears 36 and 37 (Fig. 6). Each of thegears 34 cooperating with rolls 2528 can be clutched to its shaft 32 bya clutch member 38 splined to the shaft and slidable axially intotoothed clutching engagement with its gear at 40 and 41. An operatinghandle 42 is attached to and extends forwardly from each clutch and eachclutch can be engaged and disengaged independently of the otherclutches. The teeth in the gears 34 so differ in number that when theclutches are engaged, the gears are rotatably connected to rotate therolls 2528 at progressively increasing surface speeds adapted to stretchthe material a fixed predetermined amount between each two adjacentrolls.

A like additional fixed increment of stretch is given to the materialbetween the roll 28 and the drum 14 by means of a driving connectiontherebetween. This connection includes a gear 44 fixed to the roll 11and in mesh with a gear 45. Means including sprockets and driving chains46, 4'7 and 48 directly connect the roll 11 to a shaft 5t) carrying thegear 36 and the ratio of this driving connection is such that thesurface speed of the drum 14 is greater than the surface speed of theroll 28 an amount adapted to give the desired increment of stretchtherebetween.

The roll 20 is fixed to a shaft 52 rotatably supported in fixed bearingsin the frame 33. An idler roll 54 cooperates with the roll 2t) to gripthe material 15 therebetween. The idler is rotatably supported at itsends in bearings 56 vertically movable in the frame and adapted to beforced downwardly pneumatically by pistons 57 within cylinders 58. Theshaft 52 is normally free to rotate with the roll as the material 15 isdrawn thereover, however, means is provided for placing a desired andpredetermined retarding effect on such rotation of the roll to providethe desired tension and stretch in the material at the U-loop. The meansherein illustrated comprises a rotary member fill loose on the shaft 52and driven in the direction opposite to the movement of the material,together with a friction clutch between the member and shaft. Thefriction clutch is preferably pneumatically operated and includes onefriction element carried by the member 60 and a cooperating frictionelement splined to the shaft and adapted to be forced into frictionalengagement with the first element by air pressure operating on adiaphragm. The clutch which may be of known conventional type isenclosed within a housing 62 and no novelty is claimed therefor per se.The member 60 can be conveniently driven from the shaft by a chain 64connecting a sprocket on the shaft 50 to a sprocket 65 fixed to themember 6%.

Air pressure is supplied to the housing 62 and preferably to the rear ofthe pistons 57 by a pipe 66 common to'both. This air from a source 68 isautomatically controlled by a valve within a housing 7% hereinafterdescribed. A hand-operated four-way valve 72 together with a pipe '74and an exhaust 76 are provided for conducting air forwardly of thepistons 57 and exhausting the pipe 66 when the valve is turned 90 fromthe position shown in Fig. 7.

The dancer roll 22 is mounted eccentrically on a shaft 78 rotatablysupported at its ends in fixed bearings in the frame 33, the roll beingrotatable on the eccentric bearings 79 independently of the shaft. Anarm Ed is fixed to and extends radially and horizontally from one end ofthe shaft. A rod 82 pivoted at its top end to the arm carries a valve84* on its bottom end cooperating with a valve seat within the housingW). The arm is permitted a slight movement between stops $6 and $8. Whenthe arm is engaged with the stop 86 the valve is open and when engagedwith the stop 82% the valve is closed. A rod 90 cooperating with adiaphragm 92. within a housing 94 is adapted to lift the arm by airpressure provided by a pipe 96 to the portion 66' of the pipe 66. Apressure regulator 98 and gauge 1% are provided in the pipe 96. Ableeder valve 102 is also provided in the pipe 66 for permitting aslight leakage as hereinafter described.

The invention as above described and illustrated in the drawingsprovides for giving any desired stretch from Zero to maximum to thematerial 15, the threading of the material through the machine beingidentical for all stretch requirements. it will be apparent that tensionon the material at the U-loop 21 will tend to lift the eccentricallymounted roll 22 and rock the arm 80 downwardly, thus closing the valve84. Such action together with the air leakage at the bleeder valve 192reduces the air pressure in the housing 62 and the gripping pressure ofthe roll 54 on the material and results in reducing the tension on thematerial. The common air pressure line 66 to the housing 62 and thecylinders 58 provides a varying squeeze roll pressure on the materialwhich is in direct relation with the braking torque being applied to theroll 20. The regulator 98 will initially be set at a pressure to producethe tension and stretch desired in the material at the U-loop 21 and theeecentrically operated mechanism will thereafter automatically maintainthat tension. A calibrated chart will ordinarily be provided with themachine to indicate the tensions resulting from various pressuresettings.

The increments of stretch between the adjacent rolls -28 and between theroll 28 and the drum 14 are fixed and, to give the material the requiredpercentage of stretch when it reaches the bite at the drum, it is onlynecessary to add to the initial stretch at 21 such fixed increments aswill total the desired percentage of stretch. Since the stretchincrement produced by any of the rolls 2528 can be eliminated byreleasing its clutch 38, it is only necessary to release such clutchesas will eliminate the increments not required. If, for example, allclutches 38 are released, the rolls 2523 will be entirely free and theonly stretch resulting will be such as is given at the U-loop 21. ifclutches at the rolls 25Z7 are released the stretch resulting will bethe initial stretch at 21 plus the increment between the roll 23 and thedrum 14. Thus any desired percentage of stretch can be placed in thematerial by combining the variable stretch at 21 with such of the fixedincrements as are necessary to produce the desired result. Only twoadjustments are required, namely (i) the air pressure at 98 and (2) theproper clutch engagements at 38.

When initially threading the strip material through the machine the handvalve '72 will be thrown to the broken line position of Fig. 7, thusexhausting the air above the pistons 57 and forcing the pistons and roll54 upwardly by the admission of air below the pistons. it is alsopointed out that the employment of a rotary braking torsion on the roll20 provides a smooth and uniform braking effect that is not possiblewith ordinary braking iechanisms which tend to function with a jerky andnonuniform action especially when high braking pressures are applied.

Having thus disclosed my invention what I claim as new and desire ,tosecure by Letters Patent is:

1. A machine for tensioning strip material, comprising a cylindricalrotary roll adapted to receive and support a strip of material inarcuate surface contact therewith, rotary cylindrical means beyond theroll for supporting the material and drawing it along from the roll,rotary means in frictional driving relation with the roll, means fordriving said rotary means in a direction opposite to the movement of thematerial and roll, and means cooperating with said rotary means and thematerial between the roll and rotary cylindrical means for automaticallyvarying the frictional driving torsion on the roll in inverse ratio tothe tension on the material passing from the roll to the rotarycylindrical means.

2. The machine defined in claim 1 in which said rotary means includes apneumatically operated friction clutch, and the means cooperating withthe rotary means and the material includes an air valve for the frictionclutch and cooperating mechanism disposed to cooperate with thetensioned material between the roll and rotary cylindrical means forcontrolling the valve.

3. The machine defined in claim 2 in which the means cooperating withthe rotary means and the material includes an idler roll disposed toengage a loop of said material between the first named roll and therotary cylindn'cal means, an eccentric mounting rotatably sup portingthe idler roll, a laterally extending arm fixed to the mounting, and avalve operating connection between the arm and the valve.

4. The machine defined in claim 3 in which the eccentric mounting andarm are so disposed that increased tension on the material moves the armin the valve closing direction, and resiliently operated means operativeon the arm in the valve opening direction.

5. The machine defined in claim 4 in which said resiliently-operatedmeans is pneumatically operated, and means for varying the air pressurethereto.

6. The machine defined in claim 1 in which said rotary means includes apneumatically operated friction clutch, a second roll cooperating withthe first named roll for gripping the material therebetween,pneumatically operated means for forcing the second roll into grippingrelation with the first roll, and common means under the control of saidvalve for directing air to the clutch and said pneumatically operatedmeans.

7. The machine defined in claim 1 in which said rotary cylindrical meansincludes a plurality of cylindrical stretching rolls disposed to supportsaid strip of material progressively looped arcuately on and about therolls and cylindrical means forwardly of the rolls for receiving thematerial in arcuate engagement therewith and drawing the material overthe rolls, gearing rotatably connecting said rolls to rotate atprogressively increasing surface speeds adapted to stretch the materialtherebetween, and means for individually and selectively disengaging therolls from driving engagement with the companion rolls.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Abbott Nov. 22, 1938 Young Oct. 14, 1941Gundelfinger Nov. 26, 1946 Klein et a1. Feb. 6, 1951 Bailey Mar. 20,1951 Pace Dec. 18, 1951 FOREIGN PATENTS Great Britain Sept. 13, 1946

